July 2 is World UFO Day and celebrations will be taking place around the globe, according to the World UFO Day website.

Why celebrate? To raise awareness about the "undoubted existence" of UFOs and intelligent life from outer space and to encourage governments to declassify their knowledge about sightings.

"Many governments, the U.S. government for instance, are believed to have gained exclusive information about UFOs through their military departments," according to the site. "A subject that still raises a lot of curiosity is the Roswell incident in 1947 when a believed UFO crashed in Roswell, N.M."

In the Roswell incident, eye witnesses reported seeing a brightly colored unidentified flying object before it crashed on a ranch. Pieces of the recovered wreckage contained geometric writings, according to the Roswell UFO Museum. Other eye witnesses claimed they saw alien bodies at the crash site, according to USA Today.

The Air Force first gave a statement that a flying saucer had crashed but later amended it to say the object was a weather balloon. In 1994, the Air Force issued a report saying that following exhaustive research at the request of a member of Congress, it was determined that the debris was probably from experimental surveillance balloons and the purported aliens were "anthropomorphic test dummies" inside the high altitude balloons for scientific research.

The idea of UFOs and space aliens have long been a subject of debate. Last year, a Huffington Post/YouGov poll showed that 48 percent of adults in the United States were open to the idea that alien spacecraft are observing our planet.

A World UFO Day map with notations of known celebrations of the holiday take place in scores of countries, from Venezuela to Turkey to Nigeria. There's the Hong Kong UFO Club, the Alien Society Corporation and the Dubai Research Congregation. There is also a list of the best UFO documentaries and movies, a UFO photograph collection and the top UFO landing pads.

The website provides visitors with everything from a UFO-shape database to information about the Drake Equation, a formula thought to play a role in the development of extra-terrestrial civilizations.

"It is encouraged for individual believers to organize their own parties during World UFO day," according to the website. "The most important thing is that people collectively open their minds to the subject for one day and send out the message mentally that UFO's are welcome on this earth."